1. Field of the invention
The present invention relates to an apparatus and method for controlling feed quantity and direction in a sewing machine, and more particularly to an apparatus and method for controlling feed quantity and direction of a workpiece using a motor, thereby not only allowing various patterns to be produced by stitches made up of an upper thread and a lower thread, but also allowing for a speedy sewing operation.
2. Description of the Prior Art
FIG. 1 is an exploded perspective view showing an apparatus for controlling feed quantity and direction in accordance with the prior art.
As shown in FIG. 1, conventionally, a change in the feed quantity caused by a feed dog 10 is controlled by changing a mechanical construction in such a manner that a feed regulating dial 12 is turned in a clockwise or counterclockwise direction. Further, a change in the feed direction is controlled by rotating a reverse regulating lever shaft 32 by a given angle in such a manner that either a reverse lever 13 or a reverse operation lever 50 (see FIG. 2) is pushed to drive a reverse solenoid 54 (see FIG. 2).
When the feed regulating dial 12 is turned in a clockwise or counterclockwise direction, a feed regulating dial shaft 14, which is engaged to the feed regulating dial 12, is rotated to move in a forward or backward direction. There is a threaded groove formed around the feed regulating dial shaft 14. The feed regulating dial shaft 14 is rotatably supported to an arm, which is not shown, and comes into contact with a feed regulating cam 16. Therefore, as the feed regulating dial 12 rotates, the feed regulating dial shaft 14 moves in a forward or backward direction and at the same time the feed regulating cam 16 rotates, so that a feed regulating cam connecting rod 18, which is pivotably connected to one end of the feed regulating cam 16, moves in an upward and downward direction.
When the feed regulating cam connecting rod 18 moves in an upward and downward direction, a feed regulating lever 20, which is connected to the other end of the feed regulating cam connecting rod 18 and is fixedly coupled around a reverse regulating lever shaft 32, rotates about the reverse regulating lever shaft 32. As a result, a condense regulator 24, which is fixedly coupled to the reverse regulating lever shaft 32 together with the feed regulating lever 20, also rotates In the same direction as the feed regulating lever 20.
When the condense regulator 24 rotates, a condense regulating rod 26, which is connected to the condense regulator 24, moves in a direction opposite to the feed regulating cam connecting rod 18. For instance, when the condense regulator 24 rotates in a clockwise direction, the condense regulating rod 26 moves in an upward direction, while the feed regulating cam connecting rod 18 moves in a downward direction. When an upward movement force of the condense regulating rod 26 is transmitted to a feed regulator shaft 28, the feed regulator shaft 28 is subjected to a change in a stationary angle. With the change in the stationary angle of the feed regulator shaft 28, the feed dog 10 is subjected to a change in feed quantity.
A description will be made below regarding a mechanism in which the feed dog 10 is fed according to controlled feed quantity.
As shown in FIG. 1, a feed regulator shaft 28 is connected to a feed regulator shaft connecting rod 30. The feed regulator shaft connecting rod 30 is connected to a feed cam connecting rod 36 and a feed rocker crank 33. Here, power, which is transmitted from a feed cam connecting rod 36 through the feed regulator shaft connecting rod 30 to the feed rocker crank 33, functions as a driving force allowing for movement of the feed dog 10 in a forward or backward direction. An eccentric part 44 functions as a driving source, which is formed on one end of a lower driving shaft 42 and causes a feed dog base connecting rod 46 to move in an upward and downward direction while the lower driving shaft 42 rotates. At the same time, a feed dog base 48, which is pivotably connected with the feed dog base connecting rod 46, moves in an upward and downward direction, and thereby the feed dog 10, which is attached on the upper surface of the feed dog base 48, moves in an upward and downward direction.
Subsequently, a detailed description will be made regarding a forward/backward movement transmission and an upward/downward movement transmission of the feed dog 10. The feed regulator shaft connecting rod 30 comprises a first section which is connected to the feed regulator shaft 28 and carries out a sliding motion depending on the stationary angle of the feed regulator shaft 28, a second section which is fixed to the feed cam connecting rod 36 cooperating with the feed cam 34 with the lower driving shaft 42 and carries out a fluctuating motion, and a third section which is connected to the feed rocker crank 33 fixed to a horizontal rolling pin 38 and functions as a driving source of a feed bracket 40 fixed to a horizontal rolling pin 38.
When the feed regulator shaft 28 has a constant angle, the lower driving shaft 42 receiving a rotating force from an upper driving shaft rotates. At this time, the feed cam connecting rod 36, which is connected to the feed cam 34 connected to the lower driving shaft 42 and performs an eccentric motion, moves in an upward and downward direction. The first section of the feed regulator connecting rod 30 connected to the feed regulator shaft 28 moves uniformly in an upward/downward direction and at the same time in an forward/backward direction, as shown in FIGS. 3A and 3B. Here, when the feed regulator shaft 28 is vertically fixed, the feed regulator shaft connecting rod 30 may not move in the forward/backward direction.
Therefore, the feed regulator shaft connecting rod 30 connected to the feed rocker crank 33 fluctuates in a forward/backward direction, so that the feed bracket 40 also fluctuates in a forward/backward direction. Further, the feed dog 10 moves an elliptical motion owing to an upward/downward movement transmitted from the feed cam 34 and an forward/backward movement transmitted from the feed bracket 40, as shown in FIGS. 4A to 4D. As a result, the workpiece is fed across the feed dog.
To be more specific, when an operator rotates the feed regulating dial 12 in a direction from xe2x80x9c2.5xe2x80x9d to xe2x80x9c0xe2x80x9d, a rotating force is transmitted, through the movement transmission mechanism, such as the feed regulating cam 16, feed regulator connecting rod 18, feed regulating lever 20, condense regulator 24 and condense regulating rod 26, to the feed regulator shaft 28. As a result, the stationary angle of the feed regulator shaft 28 is changed. When the feed regulating dial 12 is set to xe2x80x9c0xe2x80x9d, the rotating force, which is transmitted through the movement transmission mechanism to the feed regulator shaft 28, causes the stationary angle of the feed regulator shaft 28 to be stopped at an angle of zero degrees. Further, the feed dog 10 reciprocates in an upward/downward direction without fluctuating in a forward/backward direction.
Subsequently, an apparatus for controlling feed direction will be described. The apparatus for controlling feed direction comprises the same mechanism as the apparatus for controlling feed quantity. In other words, the apparatus for controlling feed direction has a construction which is very similar to that of the apparatus for controlling feed quantity shown in FIG. 1 as mentioned above. In particular, both apparatuses have completely the same power transmission mechanism next to the feed regulator shaft 28. Therefore, the following description regarding an operation of the apparatus for controlling a feed direction will be made only on the basis of differences from the apparatus for controlling feed quantity. When an operator presses down the reverse lever 13, the reverse regulating lever shaft 32 fastened to the reverse lever 13 by a fastening screw 15 rotates. Here, the reverse regulating lever shaft 32 rotates similarly to the feed regulating dial 12 functioning in the apparatus for controlling feed quantity, being turned in a clockwise or counterclockwise direction. As a result, a rotating movement of the reverse regulating lever shaft 32 is transmitted through the condense regulating rod 26 to the feed regulator shaft 28. In this case, a difference between the pressing of the reverse lever 13 and the turning of the feed regulating dial 12 is the movement range of the feed regulator shaft 28. To be more specific, when the feed regulating dial 12 is turned, the feed regulator shaft 28 performs a stepwise rotating movement, so that the movement range of the feed regulator shaft 28 is provided between the xe2x80x9czeroxe2x80x9d feed quantity and the xe2x80x9cmaximumxe2x80x9d feed quantity.
However, when the reverse lever 13 is pressed, the feed regulator shaft 28 is adapted to move after it rotates through the zero point as its xe2x80x9czeroxe2x80x9d feed quantity up to the maximum movement point, where the zero point refers to a stationary angle of the feed regulator shaft 28, at which, after the feed quantity is set as a xe2x80x9czeroxe2x80x9d value, the feed regulator shaft 28 causes the feed dog 10 to move in an upward/downward direction at roughly the original operating position.
For example, when the reverse lever 13 is pressed after the progressive feed quantity is set to xe2x80x9c0xe2x80x9d, the stationary angle of the feed regulator shaft 28 is not changed. However, when the reverse lever 13 is pressed after the progressive feed quantity is set to xe2x80x9c2.0 mmxe2x80x9d, the feed regulator shaft 28 rotates through the zero point up to the stationary angle corresponding to the xe2x80x9c2.0 mmxe2x80x9d value. Therefore, the feed regulator shaft connecting rod 30 connected to the feed regulator shaft 28 also moves in a forward/backward direction, so that the feed direction is changed. In this case, a condense regulating dial 11 must have a scale of 2.0 mm.
That is to say, under the preposition that the feed regulating dial 12 controlling the progressive feed quantity has a scale of 2.0 mm, when the condense regulating dial 11 limiting a reverse feed quantity has a scale of xe2x80x9c0 (zero)xe2x80x9d, the feed regulator shaft 28 maintains a stationary angle at the zero point thereof even if the reverse lever 13 is pressed. Further, when the condense regulating dial has a scale of 2.5 mm, the feed regulator shaft 28 maintains a vertical angle corresponding to the reverse feed quantity of 2.5 mm beyond the zero point.
Now, a description will be made regarding the apparatus controlling feed direction using a (semi-automated) reverse operating lever 50 with reference to FIG. 2.
When an operator operates the semi-automated reverse operating lever 50, a reverse button switch 52 is turned on to supply an electric signal to a reverse solenoid 54. Therefore, the reverse solenoid 54 is driven.
Subsequently, a driving force of the reverse solenoid 54 is transmitted to a reverse lever bracket 56 connected to the reverse solenoid 54, a reverse lever connecting link 57, a revere lever connecting bracket 58 and the reverse regulating lever shaft 32 (FIG. 1). The driving is then transmitted through the feed regulating lever 20, the condense regulator 24 and the condense regulating rod 26 (FIG. 1) to the feed regulator shaft 28 (FIG. 1).
The driving force transmitted in this manner forces the feed direction to be changed. When the reverse operating lever 50 is released, the reverse button switch 52 is turned off by a restoring force from a reverse operating lever spring 60, and then the electric signal supplied to the reverse solenoid 54 is cut off to stop the reverse solenoid 54. As a result, the reverse regulating lever shaft 32 (FIG. 1) rotates in a reverse direction, so that the feed regulator shaft 28 is returned to a position as when a forward feed is carried out.
As mentioned above, in the conventional apparatus for controlling feed quantity, there are disadvantages in that the apparatus is provided with additional components, such as the reverse lever 13, the reverse operating lever 50 and so forth, and moreover that the feed regulating dial must be manually turned by an operator during operation of the reverse solenoid 54 which is regarded to be unnecessary.
There is another disadvantage in that the operator turns the feed regulating dial 12 while seeing scales marked off by 0.5 mm increments, so that it is impossible to carry out a precise controlling operation.
Further, when a reverse lever is incorpoarted, the number of components is increased for obtaining a mechanism, and an unwanted space is needed during power transmission. Therefore, such a sewing machine has a complicated construction.
Further, response speed, which changes the feed direction, amounts to about 1000 rpm due to a property of the reverse solenoid. This acts as a great disadvantage on an industrial sewing machine which must be operated at a speed of 4500 rpm or more.
Additionally, when reverse operation is repeatedly performed, the reverse solenoid is overloaded, generating errors in that correct power transmission is not carried out and the reverse solenoid is not operated.
Accordingly, the present invention has been made to solve the above-mentioned problems occurred in the prior art, and an object of the present invention is to provide an apparatus and method for controlling feed quantity and direction in a sewing machine, in which feed quantity and direction of a workpiece are controlled using a motor, thereby not only allowing various patterns to be produced by stitches made up of upper and lower threads, but also allowing a speedy sewing operation.
It is another object of the present invention to provide an apparatus and method for controlling feed quantity and direction in a sewing machine, in which the feed quantity of a workpiece is controlled using a motor, and thereby the feed quantity can be more precisely controlled.
To achieve the above and other objects of the present invention, there is provided an apparatus for controlling feed quantity and direction in a sewing machine, the apparatus comprising: an operator interface means for inputting the feed quantity and direction of a workpiece; a motor driving control means for outputting a motor driving control signal according to feed information on the feed quantity and direction of the workpiece inputted through the operator interface means; and a workpiece feed control means for controlling rotation direction and speed of the motor according to the motor driving control signal from the motor driving control means.
It is characterized in that the sewing machine performs a sewing operation in a zigzag form while a needle bar reciprocates in an x-axis direction.
It is characterized in that the apparatus further comprises a sensing means for checking whether or not the motor is being driven and feeding the checked result back to the motor driving control means, so as to check whether or not the motor is being driven based on the feed information and correct a driving condition of the motor.
It is characterized in that the operator interface means comprises: an input section for inputting the feed quantity of the workpiece according to the operator""s plan; a select section for inputting the feed direction of the workpiece; and a display section for displaying feed information on the workpiece inputted through the input and select sections on a screen.
It is characterized in that the feed quantity of the workpiece inputted into the input section includes at least one of a progressive feed quantity and a reverse feed quantity.
It is characterized in that the motor driving control means comprises: a first control section for generating the feed information according to the feed quantity and direction of the workpiece; and a second control section for receiving the feed information by communicating with the first control section and outputting the motor driving control signal based on the feed information.
Further, it is characterized in that the motor driving control means generates a control signal for converting a position of the motor into a reference position, before generating the control signal for converting the position of the motor in response to the feed information.
It is characterized in that the feed information is stitch width information.
To achieve the above and other objects of the present invention, there is provided a method for controlling feed quantity and direction in a sewing machine, the method comprising steps of: recognizing feed quantity and direction of a workpiece inputted according to an operator""s plan; and generating feed information on the feed quantity and direction of the workpiece and controlling rotation direction and speed of a motor in response to the feed information.
It is characterized in that the method further comprises a sensing step, the sensing step being carried out by sensing whether or not the motor is being driven, feeding the sensed result back to the controlling step, checking whether or not the motor is being driven based on the feed information, and correcting a driving condition of the motor.
It is characterized in that the feed quantity of the workpiece inputted into the input section includes at least one of a progressive feed quantity and a reverse feed quantity.
It is characterized in that the controlling step further comprises a step of converting a position of the motor into a reference position, before converting the position of the motor in response to the feed information.
It is characterized in that the controlling step comprises a step of providing a correction set mode for allowing the feed information preset by the operator to be changed into desired feed information and restoring the changed resultant.
It is characterized in that the feed information is stitch width information.
The present invention is directed to propose an apparatus for controlling feed quantity and direction using a motor in a sewing machine which rotates a reverse lever shaft using the motor and a timing belt instead of rotating a feed regulating dial and includes a power transmission mechanism for connecting the reverse lever shaft, a condense regulator, a feed regulator shaft, a feed regulator shaft connecting rod, a feed rocker crank, a feed rocker bracket, a feed dog base and a feed dog. The present invention employs a mode for controlling feed quantity and direction by means of an electro-electrical mechanism using a control means and a motor, instead of controlling feed quantity and direction by means of a mechanical mechanism.